1. Field of the Invention
The present invention relates to active ingredient combinations of glyceryl glucosides and one or more acidic preservatives and the use thereof in the field of cosmetic and pharmaceutical dermatology.
In particular, the present invention relates to active ingredients and cosmetic or dermatological preparations containing such active ingredient combinations.
The present invention preferably relates to detergent cosmetic preparations.
2. Discussion of Background Information
The outermost layer of the epidermis, the stratum corneum (horny layer), is an important barrier layer of particular importance for, inter alia, protection against environmental influences and from drying out. The horny layer is continuously worn away in contact with the environment and must therefore be continuously renewed.
A skin model widely used in professional circles today regards the stratum corneum as a two-component system similar to a brick wall (brick and mortar model). In this model, the corneocytes (horny cells) correspond to the bricks, while the complex composite lipid membrane in the intercellular spaces corresponds to the mortar.
Apart from their barrier effect against external chemical and physical influences, the epidermal lipids also contribute to the cohesion of the horny layer and affect the skin smoothness. In contrast to the sebaceous gland lipids which do not form a closed film on the skin, the epidermal lipids are distributed over the whole horny layer.
The extremely complex interaction of the moisture-binding substances and the lipids of the outer skin layers is very important for the regulation of skin moisture. Therefore, cosmetics generally comprise water-binding substances in addition to balanced lipid mixtures and water. These include, inter alia, polyols such as glycerol, sorbitol and xylitol, ethoxylated polyols and hydrolysed proteins. Substances contained in the so-called natural moisturising factor (NMF) are further used, such as urea, carbohydrates (e.g. glucose) and amino acids (e.g. serine). These substances are therefore particularly important for the care performance of a cosmetic product, especially due to their relatively good skin and mucous membrane compatibility.
The desire for clean skin is probably as old as humankind, since dirt, sweat and residual dead skin particles offer the ideal breeding ground for pathogens and parasites of every type. The desire for personal hygiene steadily increased since in the 60s of the 20th century, in addition to “classical” soap, liquid detergents with newly developed synthetic surfactants were also formulated. Since then, bathing and showering are now indispensable in our daily life. Nowadays, a variety of products for the cleaning of various parts of the body are available to consumers.
Cleaning means the removal of (environmental) dirt and this causes an increase in physical and mental well-being. The cleaning of the surface of skin and hair is a very complex process dependent on many parameters. Firstly, external substances, such as hydrocarbons or inorganic pigments from different environments and also residues of cosmetics or even undesired microorganisms should be removed as completely as possible. Secondly, endogenous secretions such as sweat, sebum, skin flakes and hair dandruff should be washed off without profound changes to the physiological equilibrium.
The preserving of cosmetic preparations is a difficult task, since, on the one hand, a sufficient preservation to protect the formulation from bacterial contamination must be ensured while, on the other hand, negative influences of the preservative on the compatibility, stability and organoleptic properties of the formulation must be avoided. The preservatives must therefore be effective, toxicologically harmless, well tolerated by skin, be stable to formulation and inexpensive to produce.
A large number of preservatives, such as formaldehyde eliminators, parabens, phenols and derivatives thereof, bisguanidines and halogenated compounds, have a high antimicrobial efficacy, but can however cause skin irritation and allergic reactions and are therefore regarded critically by consumers and mostly regarded as undesirable.
One class of preservatives which are characterized by good compatibility are the organic acids effective as preservatives, particularly salicylic acid, benzoic acid, propionic acid, dehydroacetic acid (3-acetyl-6-methyl-2H-pyran-2,4(3H)-dione) and sorbic acid or the physiologically compatible water-soluble metal salts thereof.
A disadvantage of these preservatives is the fact that they are effective only at relatively high concentrations and at acidic pH. Thus, incorporation of the acids in the preparations is difficult and limited. In addition, the required concentrations lead to an impairment of the organoleptic properties and have an adverse effect on the stability of the formulation.
Thus, there is a need for preparations which overcome the disadvantages of the prior art.